CN102007704A - Apparatus and method for transmitting pilot signal in wireless communication system - Google Patents

Apparatus and method for transmitting pilot signal in wireless communication system Download PDF

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Publication number
CN102007704A
CN102007704A CN2009801136364A CN200980113636A CN102007704A CN 102007704 A CN102007704 A CN 102007704A CN 2009801136364 A CN2009801136364 A CN 2009801136364A CN 200980113636 A CN200980113636 A CN 200980113636A CN 102007704 A CN102007704 A CN 102007704A
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stream
pilot signal
signal
channel
receiver
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CN102007704B (en
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高恩锡
金殷庸
金暎秀
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0408—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas using two or more beams, i.e. beam diversity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/76—Pilot transmitters or receivers for control of transmission or for equalising
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0417—Feedback systems
    • H04B7/0421—Feedback systems utilizing implicit feedback, e.g. steered pilot signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0452—Multi-user MIMO systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842—Weighted combining
    • H04B7/0848—Joint weighting
    • H04B7/0851—Joint weighting using training sequences or error signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842—Weighted combining
    • H04B7/086—Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H04B7/024—Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Power Engineering (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Relay Systems (AREA)

Abstract

An apparatus and method for reducing pilot overhead in a multi-antenna system are provided. The method generates postcodes and pre-codes for streams used to transmit signals to at least two receivers. The method allocates a pilot signal to at least one of the streams, and allocates an additional pilot signal shared by at least one of the streams. The method precodes the pilot signal allocated to at least one of the streams, the additional pilot signal, and data to be transmitted to each of the receivers, based on the pre-code for each of the streams, prior to transmission.

Description

The apparatus and method of emission pilot signal in wireless communication system
Technical field
The present invention relates to the apparatus and method of emission pilot signal in radio communication.More specifically, the present invention relates to be used for reduce the apparatus and method of the pilot-frequency expense of multi-user multi-aerial system.
Background technology
Because the various multimedia services that are used for wireless environment are now being used or are being developed in the quick growth in mobile communication market.In wireless environment, mass data is launched so that various multimedia services are provided with two-forty.Therefore, (for example, multiple-input and multiple-output (Multiple Input Multiple Output, MIMO) system) is studied over against the multiaerial system that can use limited frequency resource more efficiently.
Compare with a single aerial system, by through being used for the independent channel emission data of each antenna, even not the outer frequency of allocation or emission (multiaerial system also can improve launcher reliability and emission rate for transmit, TX) power.In addition, multiaerial system can also improve frequency efficiency by the space resources while shared frequencies resource that is ensured by a plurality of antennas by allowing a plurality of users.After this, allow the multiaerial system of a plurality of user's shared frequencies resources will be called as multi-user multi-aerial system.
Multi-user multi-aerial system uses beam forming technique to eliminate inter-user interference.For example, multiaerial system can use associating (coordinated) beam forming technique to eliminate inter-user interference.
If multiaerial system is used the united beam forming technique, then transmitter produces preamble (pre-code) and postamble (postcode) by the downlink channel information that uses the receiver that enables in the coverage.Here, preamble and postamble have vector value or matrix value.
And receiver sends to each receiver to the quadrature dedicated pilot signal, so that receiver can detect postamble.For example, in order to give two receivers pilot signal transmission, then transmitter is distributed to each receiver to pilot tone (pilot tone) by the subchannel that uses chip architecture (tile structure) structure of constructing as shown in fig. 1.
Fig. 1 is the figure that the sub-channel structure of legacy wireless communication system is shown.
With reference to figure 1, the wireless communication system utilization makes up subchannel by the frequency resource of 4 * 3 arranged and the sheet (tile) of time resource.
Transmitter is allocation of pilots first sound and the twelfth of first receiver, and is allocation of pilots the 3rd sound and the tenth sound of second receiver, so that the pilot signal of receiver is mutually orthogonal.
In addition, transmitter uses the sound except the sound of distributing to pilot signal, is used for data transmission.
As mentioned above, transmitter is distributed to each receiver to orthogonal pilot signals.Therefore, receiver is estimated efficient channel on Liu the basis one by one by using the pilot signal of being distributed by transmitter.The efficient channel that the receiver use is estimated produces the filter of coupling, and the filter that uses the coupling that is produced is as postamble, to detect state no interference signal.Here, the filter of coupling (matched filter) provides peak signal and interference and noise ratio (Signal to Interference and Noise Ratio, postamble SINR).
Because the antenna amount of receiver is less in the united beam forming technique, therefore use the multiaerial system of united beam forming technique can launch simultaneously and the as many stream of the antenna amount of transmitter.Therefore, transmitter receiver be identified as reception (receive, RX) antenna, and simultaneously stream is transmitted to these receivers, thereby improved emission rate.
But, the increase of the quantity of the receiver of serving along with transmitter when the quantity of TX stream and when increasing, the resource that is used to distribute to the dedicated pilot signal of receiver is used also and is increased linearly, and this has increased amount of radio resources that is used for pilot signal transmission in the multiaerial system and the ratio that is used for the amount of radio resources of data transmission.
Summary of the invention
One aspect of the present invention is to solve problem above-mentioned at least and/or shortcoming, and the benefit that describes below is provided at least.Therefore, one aspect of the present invention provides the apparatus and method of the pilot-frequency expense that is used for reducing multiaerial system.
Another aspect of the present invention provides and is used for using the united beam forming technique to reduce the apparatus and method of the pilot-frequency expense of multiaerial system.
Another aspect of the present invention is the apparatus and method of pilot signal that provide the pilot signal of the reference preamble that branch is used in selection as transmitter and comprise a plurality of users' preamble in the multiaerial system of using the united beam forming technique.
Another aspect of the present invention is to provide the apparatus and method of utilizing reference pilot signal and the pilot signal that comprises multi-user's preamble to come detection signal as receiver in the multiaerial system of using the united beam forming technique.
According to an aspect of the present invention, the method that provides a kind of transmitter that is used in multiaerial system to transmit.Described method comprises: for postamble and preamble are given birth in the miscarriage that is used for signal is transmitted at least two receivers; Give in the described stream at least one allocation of pilots; Distribution is by at least one the extra pilots signal shared in the described stream; With, before emission, based on each the described preamble that is used for described stream, precoding distribute in the described stream at least one described pilot signal, described extra pilots signal and to be transmitted to each data in the described receiver.
According to a further aspect in the invention, provide a kind of method that is used at the receiver detection signal of multiaerial system.Described method comprises: estimate channel based on first pilot signal that receives by at least two streams with by second pilot signal that described stream is shared; If described first pilot signal is not to distribute to the pilot signal of the described stream of described receiver, then produce and the vector of the described channel quadrature estimated based on described first pilot signal; Produce postamble based on described orthogonal vectors; Based on described postamble and the described channel estimated according to described second pilot signal, estimate channel gain; With, based on described postamble and described channel gain detection signal.
A kind of emitter of multiaerial system is provided according to a further aspect in the invention.Described device comprises: at least two antennas; Channel detector is used for detecting the downlink channel information of at least two receivers that are positioned at the coverage; Weight generator, being used for based on described downlink channel information is that postamble and preamble are given birth in the miscarriage that is used for signal is transmitted to described receiver; Pilot controller is used at least one to described stream of allocation of pilots, and is used for distributing at least one the extra pilots signal shared by described stream; With, precoder, be used for based on each the described preamble that is used for described stream, precoding distribute in the described stream at least one described pilot signal, described extra pilots signal and to be transmitted to each data in the described receiver.
A kind of receiving system of multiaerial system is provided according to a further aspect in the invention.Described device comprises: channel estimator is used for estimating channel based on first pilot signal that receives by at least two streams and second pilot signal; The postamble generator, if being used for described first pilot signal is not to distribute to the pilot signal of the described stream of described receiving system, then based on produce postamble according to the vector of the described first pilot signal estimated channel quadrature, and, if described first pilot signal is to distribute to the pilot signal of the described stream of described receiving system, then based on producing postamble according to the described first pilot signal estimated channel; The channel gain estimator is used for estimating channel gain based on described preamble and the described channel estimated according to described first pilot signal or described second pilot signal; Back encoder is used for based on the postamble that is produced the signal that is received being carried out the back coding; With, equalizer is used for based on encoded signals behind the estimated channel gain balance.
From following detailed, others of the present invention, benefit and prominent features will become clear to those skilled in the art, and described detailed description discloses one exemplary embodiment of the present invention in conjunction with the accompanying drawings.
Description of drawings
From following description taken together with the accompanying drawings, above-mentioned and others, feature and the benefit of certain one exemplary embodiment of the present invention will be more clear, in the accompanying drawings:
Fig. 1 is the figure that the sub-channel structure of legacy wireless communication system is shown;
Fig. 2 A and Fig. 2 B are the figure that illustrates according to the efficient channel of the wireless communication system of one exemplary embodiment of the present invention;
Fig. 3 is the block diagram according to the transmitter in the wireless communication system of one exemplary embodiment of the present invention;
Fig. 4 is the block diagram according to the receiver in the wireless communication system of one exemplary embodiment of the present invention;
Fig. 5 is the flow chart that the process that transmits according to transmitter in the wireless communication system of one exemplary embodiment of the present invention is shown; With
Fig. 6 illustrates the flow chart of estimating the process of efficient channel according to receiver in the wireless communication system of one exemplary embodiment of the present invention.
Run through accompanying drawing, should notice that identical reference number is used for describing identical or similar element, feature and structure.
Embodiment
Provide following description with reference to the accompanying drawings to help complete understanding one exemplary embodiment of the present invention, the present invention is limited by claim and equivalent thereof.It comprises various details helping described understanding, but to be regarded as only be exemplary to these details.Therefore, those skilled in the art will recognize that, can make variations and modifications the embodiments described herein, and without departing from the spirit and scope of the present invention.And, for clear and succinct, omitted description to well-known functions and structure.
Employed term and words are not limited to bibliographical implication in following description and claim, and just are used for realizing knowing and consistent understanding of the present invention by the inventor.Therefore, it will be apparent to those skilled in the art that it is for illustrative purposes that following description to one exemplary embodiment of the present invention is provided, but not in order to limit purpose of the present invention, the present invention is limited by claims and equivalent thereof.
Clearly indicate in addition unless be appreciated that context, otherwise singulative " ", " one " and " being somebody's turn to do " comprise that also plural number refers to.Therefore, for example quoting of " parts surface " comprised quoting one or more this surfaces.
Show that by term " basically " characteristic, parameter or the value narrated need not accurately to reach, but the deviation or the change of the effect that described characteristic expection provides may appear not getting rid of on amount, for example comprise tolerance, measure error, measurement accuracy restriction and other factors well known by persons skilled in the art.
One exemplary embodiment of the present invention provides the scheme of the pilot-frequency expense that is used for reducing multi-user multi-aerial system.
In multiaerial system, transmitter distributes the pilot signal and the pilot signal that comprises a plurality of users' preamble that comprises with reference to the preamble vector.Here, transmitter is determined pilot signal than the stream of the quantity of the quantity little one of the antenna of receiver as the pilot signal that comprises with reference to the preamble vector, and the outer pilot signal of allocation is as the pilot signal that comprises a plurality of users' preamble.
Suppose that receiver has two antennas and makes following description.Therefore, transmitter distributes the pilot signal and the pilot signal that comprises a plurality of users' preamble that comprises with reference to the preamble vector.Even receiver has three or more antennas, transmitter also can be with distributing pilot signal with above-described essentially identical mode.
The channel variation of supposing multiaerial system slowly and have smooth fading characteristic and make following description.
Suppose that also multiaerial system uses the united beam forming technique to come interference between cancellation receiver.Here, transmitter can be launched several each receiver that flow to.But, consider the correlation between multi-user's diversity and the receiver antenna, following description hypothesis transmitter is transmitted to each receiver to a stream.
Under the situation of using the united beam forming technique, transmitter produces preamble and postamble by the downlink channel information that uses the receiver that enables in the coverage.Here, transmitter produces preamble and postamble so that the estimated efficient channel of receiver is mutually orthogonal, as shown in Figure 2.
Fig. 2 A and Fig. 2 B are the figure that illustrates according to the efficient channel of the wireless communication system of one exemplary embodiment of the present invention.
With reference to figure 2A and Fig. 2 B, under the situation of using the united beam forming technique, transmitter does not use unitary matrice (unitary matrix) when producing preamble.Therefore, as shown in Fig. 2 A, the preamble M1 of first receiver that is produced by transmitter and the preamble M2 of second receiver are non-orthogonal each other.Transmitter produces the preamble of receiver so that mutually orthogonal based on the efficient channel of being estimated by the signal of transmitter precoding/emission by receiver.
Therefore, mutually orthogonal by receiver based on the efficient channel of estimating by transmitter precoding/pilot transmitted signal, as shown in Fig. 2 B.
As mentioned above, under the situation of using the united beam forming technique, the efficient channel of the signal of transmitter precoding/emission is mutually orthogonal in receiver.Therefore, based on the orthogonality between the efficient channel, receiver can be estimated the efficient channel of himself by the efficient channel that uses another receiver.
Therefore, transmitter was distributed to reference pilot signal to the preamble vector of reference stream before emission.That is, transmitter is only distributed to reference stream to pilot signal, and this stream of precoding/emission, thereby makes and might reduce pilot-frequency expense.After passing through this reference stream received signal, the efficient channel that receiver is estimated based on the pilot signal of using reference stream produces the postamble vector.
On the other hand, by after the stream received signal except that reference stream, receiver is estimated they self efficient channel based on the efficient channel of the pilot signal estimation of this reference stream of use.After this, receiver produces the postamble vector based on estimated efficient channel.
After this, receiver uses the postamble vector that is produced that the RX signal is carried out the back coding, so that eliminate the interference that is used for the signal of other receiver with expection.
In this case, receiver can be eliminated and expect the interference of the signal that is used for other receiver, but can not compensate the channel distortion of they self signal.Receiver is estimated the channel gain of back encoded signals, so that the channel distortion of compensation RX signal.
Therefore, the outer pilot signal of transmitter allocation is so that receiver can be estimated the channel gain of back encoded signals.For example, transmitter can distribute the extra pilots signal of the preamble vector that comprises all users that served by receiver.Again for example, transmitter can distribute the extra pilots signal of the preamble vector of the user among all users that are included in by the receiver service, except the user who is assigned with reference pilot signal.Here, give each user because launch a stream, therefore a plurality of users' preamble vector is corresponding to the preamble vector of each stream.
After this, provide description to the structure of the transmitter that is used for transmitted-reference pilot signal and extra pilots signal.
Fig. 3 is the block diagram of the transmitter in the wireless communication system of the one exemplary embodiment according to the present invention.
With reference to figure 3, transmitter comprise encoder 301-1 to 301-N, modulator 303-1 to 303-N, precoder 305, radio frequency (RF) processor 307-1 be to 307-N T, channel detector 309, weight generator 311, pilot tone selector 313 and pilot controller 315.
Encoder 301-1 is suitable for the modulation and encoding scheme (the Modulation and Coding Scheme of the channel status of each receiver to each basis among the 301-N, MCS) level (level), the TX data that will be transmitted to each receiver are encoded, and encoded signals is outputed to modulator 303-1 each in the 303-N.
The signal of each received code of modulator 303-1 each in the 303-N from encoder 301-1 to 301-N, MCS level according to the channel status that is suitable for each receiver is modulated encoded signals, and the signal of modulation is outputed to precoder 305.
Precoder 305 receives preamble from weight generator 311, and the signal of reception modulation from modulator 303-1 to 303-N, utilize preamble to the modulation signal carry out precoding, and the signal of precoding output to be connected respectively to antenna RF processor 307-1 to 307-N T
Channel detector 309 detects the channel status that is used for data transmission is given the down link of the receiver that is positioned at the coverage.For example, channel detector 309 is based on the channel status of being estimated stream by the test signal (sounding signal) of receiver emission.Again for example, channel detector 309 can detect the channel condition information that is included in from the feedback signal that receiver provides.
Based on the channel information that provides from channel detector 309, weight generator 311 produces and is used for launching the preamble of data and having passed through the postamble that each stream receives the receiver of data by each stream.Here, weight generator 311 produces preamble and postamble for each receiver, so that mutually orthogonal based on the efficient channel of the signal estimation of precoding by receiver.
Pilot tone selector 313 is being used for giving the stream of the receiver that is arranged in the coverage, the reference stream that selection is used for the preamble vector is distributed to reference pilot signal data transmission.That is, pilot tone selector 313 selects to be assigned with the reference stream that is used for estimating the reference pilot signal of efficient channel by receiver.Here, before emission, the reference pilot signal of distributing to reference stream is carried out precoding by the precoding vector of reference stream, and this distributes to reference pilot signal corresponding to the precoding vector reference stream.
For example, pilot tone selector 313 is selected to come the assigned references pilot signal with the predefined stream of fixed form.
Again for example, when by each stream emission pilot signal, pilot tone selector 313 is selected the summation emission rate the highest stream of emission pilot signal with regard to all streams.If two streams are arranged, then pilot tone selector 313 is estimated the summation emission rate of all streams under the hypothesis of pilot signal by first stream emission.In addition, pilot tone selector 313 is estimated the summation emission rate of all streams under the hypothesis of pilot signal by second stream emission.After this, pilot tone selector 313 more estimated summation speed select to launch pilot signal with regard to the highest stream of summation emission rate, as the reference stream that will be assigned with reference pilot signal.Here, pilot tone selector 313 by using each stream channel information and the noise level of receiver estimate summation speed.
Again for example, pilot tone selector 313 selects the emission pilot signal just to be passed through the highest stream of minimum-signal level in each signal level that flows the pilot signal that receives by receiver.If two streams are arranged, then pilot tone selector 313 is estimated by the signal level of first and second receivers by the pilot signal of first stream reception.In addition, pilot tone selector 313 is estimated by the signal level of first and second receivers by the pilot signal of second stream reception.After this, pilot tone selector 313 by in the pilot signal estimated signals level that receives by first stream lower one and by in the pilot signal estimated signals level that receives by second stream low one compare.Then, pilot tone selector 313 selects the emission pilot signals with regard to than the highest stream of minimum-signal level in the low-signal levels, as the reference stream that will be assigned with reference pilot signal.
Again for example, pilot tone selector 313 selects the emission pilot signal just to flow the highest stream of product of the signal level of the pilot signal that receives by receiver by each.If two streams are arranged, pilot tone selector 313 is estimated by the signal level of first and second receivers by the pilot signal of first stream reception.In addition, pilot tone selector 313 is estimated by the signal level of first and second receivers by the pilot signal of second stream reception.After this, pilot tone selector 313 is being compared by the product of receiver by the signal level of the pilot signal of second stream reception by the sum of products of receiver by the signal level of the pilot signal of first stream reception.Then, pilot tone selector 313 is selected the product the highest stream of emission pilot signals with regard to the signal level that received, as the reference stream that will be assigned with reference pilot signal.
Again for example, when by each stream emission pilot signal, pilot tone selector 313 selects the emission pilot signals just by the highest stream of level of the signal of receiver reception.
Pilot controller 315 control precoders 305 are distributed to reference pilot signal to the preamble vector of the stream of being selected by pilot tone selector 313, and a plurality of users' preamble vector is distributed to the extra pilots signal.That is, pilot controller 315 control precoders 305 are only distributed to the stream of being selected by pilot tone selector 313 to reference pilot signal, and with the preamble of selected stream corresponding signal are carried out precoding.In addition, pilot controller 315 control precoders 305 are given a plurality of users' that served by receiver stream the extra pilots signal allocation, and utilize the preamble of each stream that corresponding signal is carried out precoding.
RF processor 307-1 is to 307-N TIn each from precoder 305 receiving digital signals, and digital signal is converted to analog signal.After this, RF processor 307-1 is to 307-N TIn each analog signal conversion be the RF signal, and by corresponding antenna transmitting RF signal.
After this, provide description based on the structure of the receiver of reference pilot signal that receives from transmitter and extra pilots signal detection signal.
Fig. 4 is the block diagram of the receiver in the wireless communication system of the one exemplary embodiment according to the present invention.
With reference to figure 4, receiver comprises that RF processor 401-1 is to 401-N R, back encoder 403, equalizer 405, demodulator 407, decoder 409, channel estimator 411, postamble generator 413 and channel gain estimator 415.
RF processor 401-1 is to 401-N RIn each receive RF signal by each antenna, and be this RF conversion of signals baseband signal.After this, RF processor 401-1 is to 401-N RIn each baseband signal be converted to digital signal, and output digital signal.
Channel estimator 411 from RF processor 401-1 to 401-N RReceived signal, and the pilot signal in the signal that receives based on being included in is estimated channel at transmitter.Here, channel estimator 411 is estimated efficient channel based on reference pilot signal, and estimated efficient channel is offered postamble generator 413.In addition, channel estimator 411 is estimated efficient channel based on the extra pilots signal, and estimated efficient channel is offered channel gain estimator 415.Again for example, if the preamble of reference stream is not included in the extra pilots signal, then channel estimator 411 can offer channel gain estimator 415 to the efficient channel that utilizes reference pilot signal and extra pilots signal to estimate.
Postamble generator 413 receives estimated efficient channel from channel estimator 411, and produces postamble based on the efficient channel that is received.For example, if channel estimator 411 is estimated channel based on the reference pilot signal of the stream of distributing to himself, then postamble generator 413 is discerned (recognize) for the postamble of peak signal and interference and noise ratio (SINR) is provided with the filter of coupling.
On the other hand, if channel estimator 411 is not that himself the reference pilot signal of another stream of stream is estimated channel based on distributing to, then postamble generator 413 receives estimated efficient channel from channel estimator 411, and the vector of the efficient channel quadrature that produces and received.For example, when receiving [α β] from channel estimator 411 TDuring channel, the vector [β * α] of 413 generations of postamble generator and this channel quadrature T
After this, postamble generator 413 produces the filter of coupling based on these orthogonal vectors.Here, postamble generator 413 is identified as the postamble that maximum SINR is provided with the filter of coupling.
Channel gain estimator 415 is estimated effective channel gain based on the efficient channel that receives from channel estimator 411 with from the postamble vector that postamble generator 413 receives.For example, if channel estimator 411 is estimated channel based on the reference pilot signal of the stream of distributing to himself, then channel gain estimator 415 is estimated effective channel gain as shown in following equation (1).Here equation (1) supposes that the stream that signal is transmitted to first receiver is chosen as reference stream.
Mathematics Fig. 1
[mathematics 1]
a 1 = w ~ 1 H y 1 , D 1 = | | H 1 m 1 | | . . . . . ( 1 )
Wherein, α 1The efficient channel gain that representative is estimated by first receiver,
Figure BPA00001242790800092
Represent the postamble vector of first receiver, and y 1, D1The efficient channel of representing first receiver to estimate based on reference pilot signal.
The efficient channel that channel gain estimator 415 is estimated by reference pilot signal based on the postamble vector sum is determined effective channel gain, as in equation (1).Here, if the preamble of reference pilot signal is included in the extra pilots signal, even then channel estimator 411 is estimated channel based on the reference pilot signal of the stream of distributing to himself, channel gain estimator 415 also can be determined effective channel gain, as shown in following equation (2).
On the other hand, if channel estimator 411 is not that himself the reference pilot signal of another stream of stream is estimated channel based on distributing to, then channel gain estimator 415 is determined effective channel gains, as in equation (2).Here, equation (2) supposes that the stream that signal is transmitted to first receiver is chosen as reference stream.
Mathematics Fig. 2
[mathematics 2]
α 2 = w ~ 2 H y 2 , D 2 = ( w 2 H e - j φ 2 ) ( H 2 { m 2 + m 3 + m 4 } + n 2 )
= | | H 2 m 2 | | · e - j φ 2 . . . . . ( 2 )
Wherein, α 2The efficient channel gain that representative is estimated by second receiver, y 2, D2The efficient channel of representing second receiver to estimate based on the extra pilots signal, m iRepresent the preamble vector (wherein, i comprises 2,3 and 4, and can comprise 1,2,3 and 4) of i receiver, Represent phase error, and
Figure BPA00001242790800104
The postamble vector that representative is produced based on the vector with the efficient channel quadrature of estimating according to the reference pilot signal of the reference stream of distributing to first receiver by second receiver.
Therefore,
Figure BPA00001242790800105
Can comprise the phase error as shown in following equation (3).
The extra pilots signal not only comprises the efficient channel of corresponding receiver, and comprises the efficient channel of other receiver, as in equation (2).But the postamble that receives from postamble generator 413 is used to eliminate the efficient channel of other receiver, thereby only estimates the channel gain of corresponding receiver.
Mathematics Fig. 3
[mathematics 3]
w ~ 2 = w 2 · e - jφ 2 . . . . . ( 3 )
Wherein,
Figure BPA00001242790800111
The postamble vector that representative is produced based on the vector with the efficient channel quadrature of estimating according to the reference pilot signal of the reference stream of distributing to first receiver by second receiver, w 2Represent the postamble vector of second receiver, and
Figure BPA00001242790800112
Represent phase error.
Because the postamble vector comprises phase error as in equation (3), the channel gain that produces based on the postamble vector also comprises phase error.Here, phase error is when the skew during based on postamble and channel gain detection signal of back encoder 403 and equalizer 405.
Back encoder 403 receives postamble from postamble generator 413, and use the postamble that receives to from RF processor 401-1 to 401-N RThe RX signal that receives carries out the back coding, thereby reduces the interference that is used for the signal of other receiver with expection.
Equalizer 405 gains from channel gain estimator 405 receive channels, and uses the signal of the channel gain equilibrium of reception from back encoder 403 receptions, thereby compensates the channel distortion of corresponding receiver.
Demodulator 407 is from equalizer 405 received signals, and the signal that is received according to the modulation level demodulation of correspondence.Here, modulation level comprises the MCS level.
Decoder 409 is from demodulator 407 received signals, and the signal that is received according to the modulation level decoding of correspondence, to detect initial data.
After this, provide description to the operation of transmitter transmitted-reference pilot signal and extra pilots signal.
Fig. 5 is the flow chart that the process that transmits according to transmitter in the wireless communication system of one exemplary embodiment of the present invention is shown.
With reference to figure 5, in step 501, transmitter detects the downlink channel information of the receiver that enables in the coverage.For example, transmitter can be based on estimating each downlink channel by the test signal of receiver emission.Again for example, transmitter can detect each downlink channel according to the channel condition information from the receiver feedback.
After this, in step 503, transmitter is given birth to preamble and postamble based on channel information for each miscarriage.Here, transmitter produces preamble and postamble, so that mutually orthogonal based on the efficient channel of precoded signal estimation by receiver.
After this, in step 505, transmitter selects reference stream to be used for the preamble vector is distributed to reference pilot signal.For example, transmitter is selected to come the assigned references pilot signal with the predefined stream of fixed form.Again for example, when by each stream emission pilot signal, transmitter is selected the summation emission rate the highest stream of emission pilot signal with regard to all streams.Again for example, transmitter selects the emission pilot signal just to be passed through the highest stream of minimum-signal level in each signal level that flows the pilot signal that receives by receiver.Again for example, transmitter selects the emission pilot signal just to flow the highest stream of product of the signal level of the pilot signal that receives by receiver by each.Again for example, when by each stream emission pilot signal, transmitter selects the emission pilot signal just by the highest stream of level of the signal of receiver reception.
After this, in step 507, transmitter is distributed to reference pilot signal to the preamble vector of selected stream.Here, before emission, distribute to the reference pilot signal of selected stream and utilize the preamble vector of reference stream to carry out precoding, this distributes to reference pilot signal corresponding to the preamble vector reference stream.
After this, in step 509, transmitter is distributed to the extra pilots signal to a plurality of users' that served preamble vector.For example, the transmitter handle is distributed to the extra pilots signal by all users' of receiver service preamble vector.Again for example, receiver among all users by the receiver service, the preamble vector of other user except the user who is assigned with reference pilot signal distributes to the extra pilots signal.
After this, in step 511, transmitter carries out precoding based on the preamble that produces to reference pilot signal, extra pilots signal and data in step 503, and the result is transmitted to receiver.That is, transmitter is carried out about the beam shaping of receiver based on the preamble that produces in step 503 and is operated.
After this, transmitter finishes this process.
After this, provide the description of receiver based on the operation of reference pilot signal that receives from transmitter and extra pilots signal detection signal.
Fig. 6 illustrates the flow chart of estimating the process of efficient channel according to receiver in the wireless communication system of one exemplary embodiment of the present invention.
With reference to figure 6, in step 601, receiver determines whether to receive signal from transmitter.
If then receiver advances to step 603.In step 603, the pilot signal in the signal that receiver receives based on being included in is estimated channel.Here, receiver is estimated efficient channel based on the reference pilot signal of the preamble vector that comprises reference stream, and estimates efficient channel based on the extra pilots signal of the preamble vector that comprises a plurality of users.
After this, in step 605, receiver determines whether the data of himself receive from transmitter by the stream that has been assigned with pilot signal.
If receiver is determined the data of himself and receives from transmitter by the stream that has been assigned with pilot signal that then receiver advances to step 607.In step 607, receiver produces the filter of coupling based on the efficient channel of estimating based on reference pilot signal in step 603.Here, receiver is identified as the postamble that maximum SINR is provided with the filter of coupling.
After this, in step 609, receiver is estimated channel gain based on the filter of efficient channel of estimating and coupling in step 603.For example, be not included in the extra pilots signal if be assigned with the preamble of the stream of reference pilot signal, then receiver is estimated channel gain based on the filter of coupling with according to the efficient channel that reference pilot signal is estimated, as in equation (1).Again for example, be included in the extra pilots signal if be assigned with the preamble of the stream of reference pilot signal, then receiver can be estimated channel gain based on the filter of coupling with according to the efficient channel that the extra pilots signal is estimated.
After this, in step 611, receiver detects the RX data by the signal that a filter of coupling and channel gain are applied to be received.For example, receiver uses the filter of coupling that the signal that is received is carried out the back coding, thereby reduces to be used for expection the interference of the signal of other receiver.After this, based on channel gain, encoded signals behind the receiver equalization compensating the channel distortion of himself signal, thereby detects the RX data.
On the other hand, if himself data does not receive (in step 605) by the stream that has been assigned with reference pilot signal, then receiver advances to step 613.In step 613, receiver produces and the vector of the efficient channel quadrature estimated based on reference pilot signal in step 603.For example, if be [α β] based on the reference pilot signal estimated channel T, then receiver produces and the vector [β * α] of estimated channel quadrature T
After this, in step 615, receiver produces the filter that mates based on the vector with the efficient channel quadrature.Here, receiver is identified as the postamble that maximum SINR is provided with the filter of coupling.
After this, in step 617, receiver is estimated channel gain based on the filter of efficient channel of estimating based on the extra pilots signal and coupling in step 603.Here, the extra pilots signal not only comprises the efficient channel of corresponding receiver, and comprises the efficient channel of other receiver.Therefore, receiver uses the filter of coupling to eliminate the efficient channel of other receiver, thereby only estimates the channel gain of himself.
After this, in step 611, receiver detects the RX data by the signal that a filter of coupling and channel gain are applied to be received.For example, receiver uses the filter of coupling that the signal that is received is carried out the back coding, thereby reduces to be used for expection the interference of the signal of other receiver.After this, based on channel gain, encoded signals behind the receiver equalization compensating the channel distortion of himself signal, thereby detects the RX data.
After this, receiver this process as a result.
In the superincumbent one exemplary embodiment, receiver can by distribution comprise a plurality of users the preamble vector the extra pilots signal and reduce pilot-frequency expense than the reference pilot signal of the stream of the quantity of the antenna amount little of receiver.
In another one exemplary embodiment, transmitter can reduce pilot-frequency expense by only using common pilot signal.
According to above-described one exemplary embodiment of the present invention, the transmitter of multiaerial system comprise by distribution a plurality of users preamble pilot signal and be used for transmitting with reference to the pilot signal of preamble vector, thereby make and might reduce pilot-frequency expense and to improve spectrum efficiency.
Though illustrate and described the present invention with reference to certain one exemplary embodiment of the present invention, but it will be appreciated by those skilled in the art that the various variations on the form of to make and the details, and do not depart from the spirit and scope of the present invention that limit by claims and equivalent thereof.

Claims (21)

1. method that the transmitter that is used in multiaerial system transmits, described method comprises:
Each produces postamble and preamble signal is transmitted in the stream of two receivers at least in order to be used for;
Give in the described stream at least one allocation of pilots;
Distribution is by at least one the extra pilots signal shared in the described stream; With
Before emission, based on each the described preamble that is used for described stream, precoding distribute in the described stream at least one described pilot signal, described extra pilots signal and to be transmitted to each data in the described receiver.
2. the method for claim 1, wherein produce described preamble and described postamble comprises:
Detect downlink channel information; With
Produce each described preamble and the described postamble that is used for described stream based on described downlink channel information, so that described receiver is mutually orthogonal based on the estimated efficient channel of the signal of precoding.
3. the method for claim 1, wherein the distribution of described pilot signal comprises:
Select at least one will be assigned with the stream of described pilot signal based on downlink channel information; With
Give selected stream described allocation of pilots.
4. method as claimed in claim 3, wherein, the selection of described at least one stream comprises:
By use following scheme one of them, selection will be assigned with the stream of described pilot signal: the scheme of selecting stream with fixed form, selection is with regard to the scheme of the highest stream of the summation emission rate of all streams, selection is transmitted in by the scheme of receiver at the stream of the pilot signal that has the highest signal level in each the pilot signal estimated signals level by the stream emission, select the emission pilot signal just by the scheme of described receiver, and select to make scheme when the highest stream of the level by flowing when launching described pilot signal the signal that will be received by described receiver at the highest stream of the product of each the pilot signal estimated signals level by the stream emission.
5. the method for claim 1, wherein the distribution of described pilot signal comprises:
Lack the stream of one quantity for antenna amount than described receiver described allocation of pilots.
6. the distribution of the method for claim 1, wherein described extra pilots signal comprises:
Be distributed in and be used for signal is transmitted at least two streams of at least two receivers, is assigned with the described extra pilots signal that other stream beyond the stream of described pilot signal is shared.
7. the distribution of the method for claim 1, wherein described extra pilots signal comprises:
Distribute the shared described extra pilots signal of all streams that is used to signal is transmitted at least two receivers.
8. method that is used at the receiver detection signal of multiaerial system, described method comprises:
Estimate channel based on first pilot signal that receives by at least two streams with by second pilot signal that described stream is shared;
If described first pilot signal is not to distribute to the pilot signal of the stream of described receiver, then produce and the vector of the described channel quadrature estimated based on described first pilot signal;
Produce postamble based on described orthogonal vectors;
Based on described postamble and the described channel estimated according to described second pilot signal, estimate channel gain; With
Based on described postamble and described channel gain detection signal.
9. method as claimed in claim 8, wherein, described postamble comprises the filter of the coupling that produces based on described orthogonal vectors.
10. method as claimed in claim 8, wherein, the detection of described signal comprises:
By using described postamble the signal that is received is carried out precoding; With
Based on encoded signals after the described channel gain equilibrium.
11. method as claimed in claim 8 also comprises:
If described first pilot signal is to distribute to the pilot signal of the described stream of described receiver, then produce postamble based on the described channel of estimating according to described first pilot signal;
Based on described postamble and the described channel estimated according to described first pilot signal, estimate channel gain; With
Based on described postamble and described channel gain detection signal.
12. method as claimed in claim 8 also comprises:
If described first pilot signal is to distribute to the pilot signal of the described stream of described receiver, then produce postamble based on the described channel of estimating according to described first pilot signal;
Based on described postamble and the described channel estimated according to described second pilot signal, estimate channel gain; With
Based on described postamble and described channel gain detection signal.
13. the emitter of a multiaerial system, described device comprises:
At least two antennas;
Channel detector is used for detecting the downlink channel information of at least two receivers that are positioned at the coverage;
Weight generator, being used for based on described downlink channel information is that postamble and preamble are given birth in the miscarriage that is used for signal is transmitted to described receiver;
Pilot controller is used at least one to described stream of allocation of pilots, and is used for distributing at least one the extra pilots signal shared by described stream; With
Precoder is used for based on each the described preamble that is used for described stream, precoding distribute in the described stream at least one described pilot signal, described extra pilots signal and to be transmitted to each data in the described receiver.
14. device as claimed in claim 13, wherein, described weight generator produces each described preamble and the described postamble that is used for described stream based on described downlink channel information, so that described receiver is mutually orthogonal based on the estimated efficient channel of the signal of precoding.
15. device as claimed in claim 13 also comprises selector, is used for the stream of selecting at least one will be assigned with described pilot signal based on described downlink channel information,
Wherein said pilot controller is given each stream of being selected by described selector described allocation of pilots.
16. device as claimed in claim 15, wherein, described selector by use following scheme one of them, selection will be assigned with the stream of described pilot signal: the scheme of selecting described stream with fixed form, selection is with regard to the scheme of the highest stream of the summation emission rate of all streams, selection is transmitted in by the scheme of described receiver at the stream of the pilot signal that has the highest signal level in each the pilot signal estimated signals level by the stream emission, select the emission pilot signal just by the scheme of described receiver, and select to make scheme when the highest stream of the level by flowing when launching described pilot signal the signal that will be received by described receiver at the highest stream of the product of each the pilot signal estimated signals level by the stream emission.
17. device as claimed in claim 13, wherein, described pilot controller lacks the stream of one quantity for described allocation of pilots antenna amount than described receiver.
18. device as claimed in claim 13, wherein, described pilot controller is distributed in and is used for signal is transmitted at least two streams of at least two receivers, is assigned with the described extra pilots signal that other stream beyond the stream of described pilot signal is shared, and perhaps distributes to be used to signal is transmitted to the described extra pilots signal that all streams of at least two receivers are shared.
19. the receiving system of a multiaerial system, described device comprises:
Channel estimator is used for estimating channel based on first pilot signal that receives by at least two streams and second pilot signal;
The postamble generator, if being used for described first pilot signal is not to distribute to the pilot signal of the described stream of described receiving system, then based on produce postamble according to the vector of the described first pilot signal estimated channel quadrature, and, if described first pilot signal is to distribute to the pilot signal of the described stream of described receiving system, then based on producing postamble according to the described first pilot signal estimated channel;
The channel gain estimator is used for estimating channel gain based on described preamble and the described channel estimated according to described first pilot signal or described second pilot signal;
Back encoder is used for based on the postamble that is produced the signal that is received being carried out the back coding; With
Equalizer is used for based on encoded signals behind the estimated channel gain balance.
20. device as claimed in claim 19, wherein, described postamble generator produces the filter of coupling as described postamble based on described orthogonal vectors.
21. device as claimed in claim 19, wherein, if described first pilot signal is to distribute to the pilot signal of the described stream of described receiving system, then described channel gain estimator is based on described postamble and the described channel gain of described channel estimating estimated according to described second pilot signal, perhaps, based on described postamble and the described channel gain of described channel estimating estimated according to described first pilot signal or described second pilot signal.
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